The present invention relates to a calcium phosphate-synthetic resin composite body having excellent workability, impact resistance and water resistance as well as high biocompatibility, and a method for the production thereof.
Calcium phosphate is utilized for biomaterials such as artificial dental roots, bone reinforcements and dental cements because of excellent biocompatibility. However, it is poor in toughness due to its nature as a ceramic and cannot be used for members requiring impact resistance. Thus, artificial dental roots and bone reinforcements are made of metallic materials, which are not harmful to the human body, such as titanium and stainless steel. However, because calcium phosphate compounds, particularly hydroxyapatite, are much better in terms of biocompatibility, their use has been desired.
Under such circumstances, attempt has been made to combine calcium phosphate compounds with glass materials, metallic materials and synthetic resins, and some of the resultant composite bodies have been already put into practical use. However, when they are combined with the glass materials, there are problems that the glass elutes from the resultant composite bodies into the human body as time goes on, and that the composite bodies lack toughness.
The composite material of the calcium phosphate compound and the metallic material is obtained by charging the calcium phosphate compound particles into a metal frame or sintering a mixture of metal powder and the calcium phosphate compound powder. In the former case, however, the calcium phosphate compound is likely to move from the metal frame in the body. In the latter case, the calcium phosphate compound particles exposed on the surface of the sintered composite body are easily detached.
Though attempt has been made to blend a molten synthetic resin and calcium phosphate particles to provide their composite body, the calcium phosphate particles easily collapse during blending, and the molten synthetic resin easily covers the calcium phosphate particles in the course of molding the composite body. In addition, burring disadvantageously occurs during cutting.
Though attempt is also made to combine a composite body of calcium phosphate particles and cross-linked, synthetic resin particles with a highly biocompatible calcium phosphate block, the calcium phosphate block is easily detached. Also, because the calcium phosphate block is poor in toughness, it disadvantageously collapses in the course of molding.